An electronic device is a device that performs a specific function according to a program provided therein, such as an electronic scheduler, a portable multimedia reproducer, a mobile communication terminal, a tablet PC, an image/sound device, a desktop/laptop PC, or a vehicular navigation system, as well as a home appliance. For example, such an electronic device may output information stored therein as sound or an image. As the degree of integration of such an electronic device has increased, and super-high speed and large-capacity wireless communication has become popular, various functions have recently been provided together in a single mobile communication terminal. For example, various functions, such as an entertainment function (e.g., a game function), a multimedia function (e.g., a music/video reproduction function), a communication and security function for mobile banking, a schedule management function, and an e-wallet function, are integrated in a single electronic device, in addition to a communication function.
Electronic devices are capable of outputting information, such as an image, text, and a video image by including a display device. Display device have been developed from a vacuum tube type to a flat plate type, and it has become possible to provide a larger screen as the volumes of household appliances, such as televisions, have been drastically reduced. Further, it has also become possible to provide high-quality image information through a miniaturized electronic device, such as a mobile communication terminal.
An electronic device, such as a mobile communication terminal, may be configured to be foldable so as to ensure portability. When a flexible display device is mounted on a foldable electronic device, the portability of the electronic device can be maintained or improved while providing a larger screen in an expanded state.
Such a display device may include a display element that outputs a screen and a window member that protects the display element. The window member may have sufficient strength to protect the display element from the external environment and sufficient transparency to transmit the screen output from the display element therethrough. Further, in order to prevent deterioration of image quality due to scratches or the like of the window member, the surface hardness of the window member may be strengthened by forming a hard coating layer on the surface of the window member using a ceramic, acryl, or the like.